Griffith brewer



G. BREWER.

ADJUSTABLE DIAL FOR PRESSURE GAGES AND LIKE'DIAL INSTRUMENTS.

APPLICATION FILED ocr. 31. 1918.

GRIFFITH BREWER, OF LONDON, ENGLAND.

ADJUSTABLE DIAL FOR PRESSURE-GAGES AND LIKE DIAL INSTRUMENTS.

Specification of Letters Patent.

Patented Jan. 2'7, 1920.

Application filed October 31. 1918. Serial N 0. 260,570.

To all whom it may concern:

Be it known that I, GRIFFITH Bnnwnn, a subject of the King of Great Britain, residing at London, England, have invented certain new and useful Improvements in Adjustable Dials! for Pressure-Gages and llke Dial Instruments, of which the following is a specification.

The present invention refers to an angularly adjustable dial for pressure gages and air speed indicators, particularly such as are employed on aircraft, said dial being also applicable to other like instruments.

According to this invention the dial, which is of annular type composed of sheet metal or other suitable material having the requisite elasticity, is formed with its internal periphery eccentric to its external periphery, the axis of the finger of the instrument, which finger indicates upon index or graduation marks on the face of the dial adjacent to the inner periphery thereof, being concentric with the said inner peripheryof the dial.

The face of such a dial, owing to the con-- struction described, is consequently narrow at one part and increases gradually in width to a point diametrically opposite to the narrower part of the said dial, and at the said narrower part the material of the dial is divided, a small space being formed between the divided ends thereof, so that when the divided ends are brought together or nearly so, the diameter of the annular dial is lessened, and owing to the width of the face of the dial increasing from both divided ends, in opposite directions, to a point diametrically opposite such divided ends, consequently the strength thereof is increased in proportion to the length of the leverage exerted when the distance apart of the divided ends is" varied.

Such a dial is located in an annular groove in the case of the instrument, or in an annular groove formed in a bezel ring secured thereto, the external diameter of the dial being slightly greater than the internal diameter of the groove in which it fits, the said dial being inserted into the groove by slightly pressing the divided ends of the said dial together and then releasing the same when in position. Thus the dial can be angularl adjusted by pressing the divided ends thereof toward each other and moving the dial around in its carrying groove, and upon the divided ends being released the dial will be firmly held in the position in which it has been placed.

To facilitate the operation of such a dial the divided ends may be formed with inward projections to be gripped by the fingers of the operator.

The invention will be described with reference to the accompanying drawings, whereon the dial is shown applied to a pressure gage of a type to which it is particularly suited and upon which it can be used with considerable advantage, such types of pressure; gage forming the subjects of Alec Ogilvies United States Patent No. 1146202, dated the 13th July, 1915, and my United Staltles patent application of even date herewit Figure 1 of the aforesaid drawings shows j tion to the outer periphery 3, and-on the face. 1 of the dial adjacent to the innerperiphery 2 are indicated any required'index marks or graduations 4:, 5 indicating the zero mark.

' By this construction itwill be observed that at one part the face of the dial is narrow and the width of the face of the dial increases gradually to a point diametrically opposite the narrower pa'rt, in" the example now shown the widest part "ofthe dial being at about the zero point 5. The narrower part of the dial 6 is divided, a small space being formed between the divided ends, the said divided ends having inward projections 7, 8 which may be gripped by the operator when it is desired to contract the external diameter of the dial.

The dial is shown applied at Figs. 2 and 3 to a pressure gage, which as aforesaid corresponds to that described in my patent application of even date herewith, and the constructional details and the working of such a gage need not therefore be set out in detail, it being suflicient to remark that it is an instrument comprising a case 9 containing an elastic diaphragm 10 which divides the interior of the case into two compartments, the front compartment being closed by a transparent cover 11, and mechanism is rovided in the front compartment for angu arly moving a spindle 12 carrying an indicating finger 13 beneath the transparent cover 11, the said finger moving in accordance with the movements of the elastic diaphragm 10 produced by differing pressures admitted to the compartments on each side of the diaphragm.

The case 9 is fitted with a flanged locking ring 14 which in this case retains and presses the transparent cover 11 to the case 9, and the locking ring is formed with an annular groove or rabbet into which the dial described at Fig. 1 is fitted, it being observed that the axis of the indicating finger 13 is about concentric with the inner periphery 2 of the dial 1.

It will now be understood that by the operator gripping the inward projections 7, 8 of the dial and pressing the same toward each other, the dial can be adjusted relatively to the case and the zero mark 5 can be set opposite to the indicating finger when the latter is at rest.

What I claim as my invention and desire to secure by Letters Patent is 1. In pressure gages and the like dial instruments; an annular dial of sheet material of the requisite elasticity, having an internal periphery eccentric to an external periphery to constitute a face surface narrow at one part and increasing gradually in width in both directions from such narrower part to a point diametrically opposite to said narrower part, said dial being divided at its narrower part into adjacent ends said division leaving a small space between said adjacent ends, said dial being adapted tobe inserted into an annular groove in a case by causin the adjacent ends of said dial to approac each other and the release of said adjacent ends and consequent expension of said dial frietionally holding same in position.

2. In pressure gages and the like dial instruments; an annular dial of sheet material of the requisite elasticity, having an internal periphery eccentric to an external periphery to constitute a face surface narrow at one part and increasing gradually in width in both directions from such narrower part to a point diametrically opposite to said narrower part, said dial being divided at its narrower part into adjacent ends, said division leaving a small space between said adjacent ends, each end of said dial at said division having inwardly extending projections to be gripped by the operator to contract the diameter of the dial and to angularly adjust the same, said dial being adapted to be inserted into an annular groove in a case by causing the adjacent ends of said dial to approach each other and the release of said adjacent ends and consequent elastic expansion of said dial frictionally holding same in position.

3. In pressure gages and the like dial instruments; an annular dial of sheet material of the requisite elasticity having an internal periphery eccentric to an external periphery to constitute a face surface narrow at one point and increasing gradually in width in both directions from such narrower part to a point diametrically opposite to said narrower part, said dial being divided at its narrower part into adjacent ends said division leaving a small space between said adjacent ends, a graduated index or scale on the face of said dial adj acent to the internal periphery of said dial, an instrument case having an annular groove of an internal diameter slightly less than the normal diameter of said dials external periphery, said dial being adapted to be inserted into said case groove by causing the adjacent ends of said dial to approach each other and the release of said adjacent ends and consequent elastic expansion of said dial frictionally holding same 1n POSI- tion.

In witness whereof I have hereunto set my hand in the presence of two witnesses.

GRIFFITH BREWER.

Witnesses:

THOMAS W. Rooms, WILLIAM A. MARSHALL. 

